Well Systems and Associated Methods Incorporating Fluid Loss Control

ABSTRACT

A method of controlling fluid loss from a wellbore comprises the steps of: installing a completion string including a well screen and a fluid loss control device in the wellbore; then installing a production string in the wellbore; then engaging the production string with the completion string; and then operating the fluid loss control device by varying pressure in a fluid passage. A well system comprises a completion string including a fluid loss control device, a packer and a well screen, the packer being positioned between the fluid loss control device and the screen; and a production string including another packer and engaged with the completion string, the fluid loss control device being positioned longitudinally between the packers, and the fluid loss control device being operable in response to variation of pressure in a fluid passage.

BACKGROUND

The present disclosure relates generally to equipment utilized andoperations performed in conjunction with a subterranean well and, in anembodiment described herein, more particularly provides well systems andmethods incorporating fluid loss control.

A gravel pack assembly typically includes a packer, a closing sleeve, afluid loss device and a well screen, with a work string and amulti-position tool engaged within the assembly. A flowpath is providedin the gravel pack assembly for delivery of stimulation fluids and agravel slurry into a wellbore external to the assembly, and anotherflowpath is provided for circulating fluids back to surface. Once theoperation is completed, the multi-position tool and work string areretrieved.

The fluid loss control device is usually closed upon retrieval of thework string and multi-position tool, in order to prevent loss of fluidfrom the wellbore. The fluid loss control device is usually opened uponinstallation of a production string, to thereby allow for production offluid to the surface via the production string.

Unfortunately, the fluid loss control device cannot be convenientlyclosed again if there is a need to retrieve the production string, or tocarry out other operations, such as chemical washouts for hydrateremediation. In some circumstances, a wireline- or coiledtubing-conveyed shifting tool can be used to close the fluid losscontrol device, but this requires intervention into the productionstring, and is costly and inconvenient (particularly if the productionstring needs to be urgently retrieved, such as during an emergency, orif production is via a floating production storage and offloading (FPSO)facility).

Therefore, it will be appreciated that improvements are needed in theart of fluid loss control. These improvements may be useful inoperations other than those discussed above.

SUMMARY

In the present specification, well systems and methods are providedwhich solve at least one problem in the art. One example is describedbelow in which a fluid loss control device is operable multiple timeswithout physical intervention. Another example is described below inwhich annulus pressure or conduit pressure can be used to close a fluidloss control device after it has been opened.

In one aspect, a method of controlling fluid loss from a wellbore isprovided. The method includes the steps of: installing a completionstring in the wellbore, the completion string including a well screenand a fluid loss control device; then installing a production string inthe wellbore; then engaging the production string with the completionstring; and then operating the fluid loss control device by varyingpressure in a fluid passage (such as a conduit and/or an annulus formedbetween the wellbore and the production string).

In another aspect, a well system for use in a wellbore is provided whichincludes a completion string including a fluid loss control device, apacker and a well screen. The packer is positioned longitudinallybetween the fluid loss control device and the well screen. A productionstring is engaged with the completion string, and the production stringincludes another packer. The fluid loss control device is positionedlongitudinally between the packers, and the fluid loss control device isoperable in response to variation of pressure in a fluid passage (suchas a conduit and/or an annulus formed between the wellbore and theproduction string).

In yet another aspect, a method of controlling fluid loss from awellbore includes the steps of: installing a completion string in thewellbore, the completion string including a well screen and a fluid losscontrol device; then installing a production string in the wellbore;then engaging the production string with the completion string; thenopening the fluid loss control device; and then closing the fluid losscontrol device without intervention into the production string.

These and other features, advantages and benefits will become apparentto one of ordinary skill in the art upon careful consideration of thedetailed description of representative embodiments below and theaccompanying drawings, in which similar elements are indicated in thevarious figures using the same reference numbers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic partially cross-sectional view of a well systemand associated method embodying principles of the present disclosure;

FIG. 2 is a schematic partially cross-sectional view of the well systemafter further steps in the method have been performed;

FIG. 3 is an enlarged scale schematic cross-sectional view of a fluidloss control device usable in the well system and method;

FIG. 4 is a schematic partially cross-sectional view of anotherconfiguration of the well system and its associated method;

FIG. 5 is a schematic partially cross-sectional view of anotherconfiguration of the well system and its associated method;

FIG. 6 is a schematic partially cross-sectional view of anotherconfiguration of the well system and its associated method;

FIG. 7 is a schematic partially cross-sectional view of anotherconfiguration of the well system and its associated method;

FIG. 8 is a schematic partially cross-sectional view of anotherconfiguration of the well system and its associated method;

FIG. 9 is a schematic partially cross-sectional view of anotherconfiguration of the well system and its associated method; and

FIG. 10 is a schematic partially cross-sectional view of anotherconfiguration of the well system and its associated method.

DETAILED DESCRIPTION

It is to be understood that the various embodiments described herein maybe utilized in various orientations, such as inclined, inverted,horizontal, vertical, etc., and in various configurations, withoutdeparting from the principles of the present disclosure. The embodimentsare described merely as examples of useful applications of theprinciples of the disclosure, which are not limited to any specificdetails of these embodiments.

In the following description of the representative embodiments of thedisclosure, directional terms, such as “above”, “below”, “upper”,“lower”, etc., are used for convenience in referring to the accompanyingdrawings. In general, “above”, “upper”, “upward” and similar terms referto a direction toward the earth's surface along a wellbore, and “below”,“lower”, “downward” and similar terms refer to a direction away from theearth's surface along the wellbore.

Representatively illustrated in FIG. 1 is a well system 10 andassociated method which embody principles of the present disclosure. Inthe system 10, a completion string 12 has been installed in a wellbore14, and a gravel packing operation has been performed. The wellbore 14is depicted in FIG. 1 as being cased, but it is not necessary for thewellbore to be cased, or for a gravel packing operation to be performedin keeping with the principles of this disclosure.

The completion string 12 preferably includes a specialized gravelpacking or frac-pack packer 16, a closing sleeve 18, a fluid losscontrol device 20 and a well screen 22. A work string 24 is engaged withthe completion string 12 during installation and subsequentstimulation/gravel packing operations. The work string 24 includes amulti-position tool 26, seals 28 and washpipe 30. Many additionalcomponents, other components and combinations of components can beincluded in the completion and work strings 12, 24 in keeping with theprinciples of this disclosure.

After the wellbore 14 has been gravel packed about the screen 22, thework string 24 is retrieved from the well and the fluid loss controldevice 20 is closed to prevent loss of fluid from the wellbore 14 (orthe interior of the casing if the wellbore is cased) during retrieval ofthe work string and installation of a production string 32 (not shown inFIG. 1, see FIG. 2). Except for the fluid loss control device 20, all orany of the components depicted in FIG. 1 may be conventional componentsof the type well known to those skilled in the art.

Referring additionally now to FIG. 2, the well system 10 is depictedafter installation of the production string 32. The production string 32is inserted into the completion string 12 and is sealingly engagedtherein with seals 34 The production string 32 is also sealed andsecured in the wellbore 14 using a packer 36.

An annulus 38 is formed radially between the production string 32 andthe wellbore 14 (or the interior surface of the casing if the wellboreis cased), and another annulus 40 is formed radially between thecompletion string 12 and tubing 42 of the production string 32. Theannulus 38 is in fluid communication with the annulus 40 via an opening44 in the completion string 12 above the packer 16, an opening throughthe packer 36, and another annulus 48 between the packers.

In one unique feature of the system 10, the fluid loss control device 20can be operated by varying pressure in the annulus 38 (for example,using a pump or other pressurized fluid source at the surface ormudline), which pressure is communicated to the fluid loss controldevice via the openings 44, 46 and annuli 40, 48. In this manner, thefluid loss control device 20 can be operated even after the work string24 has been retrieved, and can be operated multiple times after theproduction string 32 is installed, as desired.

The fluid loss control device 20 may also be operable multiple times byvarying pressure in an interior flow passage 50 of the production string32. For example, the fluid loss control device 20 may be opened byincreasing pressure in the flow passage 50, and the fluid loss controldevice may be closed by increasing pressure in the annulus 38.

Referring additionally now to FIG. 3, an example of a fluid loss controldevice 20 which may be used in the system 10 and associated method isrepresentatively illustrated. As depicted in FIG. 3, the device 20includes a ball valve 52 and an actuator 54.

When interconnected in the completion string 12, and with the productionstring 32 sealingly engaged therein, the flow passage 50 extends throughthe device 20. A piston 56 of the actuator 54 has one side exposed topressure in the passage 50 via an opening 58, and an opposite sideexposed to pressure in the annulus 40 via an opening 60. A seal bore 62is provided for sealing engagement with the seal 34 at the lower end ofthe tubing 42.

It will be readily appreciated that when pressure in the passage 50 isincreased until it is greater than pressure in the annulus 40, thepiston 56 will displace upward and open the ball valve 52. When pressurein the annulus 40 is subsequently increased until it is greater thanpressure in the passage 50, the piston 56 will displace downwardly toclose the ball valve 52, as depicted in FIG. 3.

Of course, the device 20 as depicted in FIG. 3 is merely one simplifiedexample of a fluid loss control device which may be used in the system10. Additional features may be incorporated into the device 20 (such as,shear pins, latches, ratchets, pressurized gas chambers, etc.) tocontrol how and when the device operates, different types of valves maybe used (such as flappers, etc.), and other variations may be used inkeeping with the principles of this disclosure.

Referring additionally now to FIG. 4, another configuration of thesystem 10 is representatively illustrated. This configuration is similarin many respects to the system 10 of FIG. 2, but differs at least inpart in that the production string 32 includes a fluid loss controldevice 20 interconnected below the packer 36.

In addition, the production string 32 includes a latching device 64 forreleasably securing the production string to the packer 16 of thecompletion string 12, a latching device 66 for releasably securing theproduction string to the upper fluid loss control device 20, atelescoping travel joint 68 positioned between the packer 36 and thelatching device 66, and a conduit 70 for providing fluid communicationbetween the opening 46 and the latching device 66. The latching device66 includes a flowpath (not visible in FIG. 4) for providing fluidcommunication between the conduit 70 and the opening 60 in the upperdevice 20, so that pressure in the annulus 38 is communicated to theactuator 54 of the upper device.

Thus, the upper device 20 is operable in response to varying pressure inthe annulus 38, and is operable in response to varying pressure in thepassage 50, as in the description above relating to FIG. 3. However, inthe system 10 of FIG. 4, the upper device 20 is positionedlongitudinally between the packers 16, 36.

Preferably, the upper fluid loss control device 20 is installed with theproduction string 32, with the latching device 64 being used to securethe production string (including the device) to the completion string12. However, if it should become necessary to retrieve the productionstring 32, the upper device 20 can be closed (for example, bypressurizing the annulus 38), and the production string can bedisconnected from the upper device 20 at the latching device 66.

Closing of the upper device 20 will, thus, conveniently prevent loss offluid from the wellbore 14. The latching device 66 will also permitconvenient reconnection of the production string 32 to the upper device20, with pressure in the passage 50 being used to reopen the valve 52when desired. This process can be repeated any number of times.

Note that the latching device 66 also serves as a hydraulic wet connectbetween the upper device 20 and the conduit 70. Fluid communicationbetween the upper device 20 and the conduit 70 can be connected ordisconnected using the latching device 66 any number of times.

Alternatively, the travel joint 68 may be used for disconnecting theproduction string 32. For example, the travel joint 68 could be shearpinned open during installation, with set down weight being used toshear the pins and activate the travel joint when in position.

The production string 32 could then separate at the latching device 66when it is necessary to retrieve the production string. A wet connect 72(described below) could be used to reconnect the conduit 70 to the upperdevice 20 when the production string 32 is again installed. The latchingdevice 64 may be used to retrieve and reinstall the upper device 20, ifdesired.

Referring additionally now to FIG. 5, another configuration of thesystem 10 is representatively illustrated. This configuration is similarin many respects to the system 10 of FIG. 4, but differs at least inpart in that the latching device 64 is not used to releasably secure theproduction string 32 to the completion string 12. Instead, the upperfluid loss control device 20 is preferably installed as part of thecompletion string 12, and the production string is releasably secured tothe completion string using the latching device 66 when it is installed.

Preferably, the upper device 20 is constructed as part of the packer 16,or at least is connected thereto when the completion string 12 isinstalled. The lower device 20 may be used as in conventionalstimulating/gravel packing operations to prevent fluid loss, while theupper device 20 remains open. However, after the production string 32 isinstalled, the upper device 20 is then operable as needed to preventfluid loss.

Alternatively, the lower device 20 may not be used, in which case theupper device 20 could be closed by the multi-position tool 26 when thework string 24 is retrieved from the well. In this manner, theadditional lower device 20 would not be needed.

As described above, the upper device 20 is operable by varying pressurein the annulus 38 and passage 50 to selectively open and close thedevice. However, in the configuration of FIG. 5, a separate hydraulicwet connect 72 is used between the conduit 70 and the upper device 20.Such a wet connect 72 may be used in the configuration of FIG. 4, ifdesired.

Thus, in the event that the production string 32 needs to be retrievedfrom the well, the upper device 20 will be closed (for example, bypressurizing the annulus 38), the production string will be disconnectedfrom the completion string 12 at the latching device 66, and the wetconnect 72 will be disconnected. When the production string 32 isinstalled again, the wet connect 72 will again provide fluidcommunication between the upper device 20 and the annulus 38.

Referring additionally now to FIG. 6, another configuration of thesystem 10 is representatively illustrated. This configuration is similarin most respects to the configuration of FIG. 4, but differs at least inthat the upper packer 36 is not used on the production string 32, andthe conduit 70 extends to a remote location (such as the earth'ssurface, the mudline in a subsea application, or another location in thewell).

In the configuration of FIG. 6, pressure is applied to the valve device20 via the conduit 70 from the remote location, instead of being appliedvia the annulus 38. Otherwise, this configuration of the system 10operates in the same manner as the configuration of FIG. 4.

Referring additionally now to FIG. 7, another configuration of thesystem 10 is representatively illustrated. This configuration is similarin most respects to the configuration of FIG. 5, but differs at least inthat the upper packer 36 is not used on the production string 32, andthe conduit 70 extends to a remote location (such as the earth'ssurface, the mudline in a subsea application, or another location in thewell).

In the configuration of FIG. 7, pressure is applied to the valve device20 via the conduit 70 from the remote location, instead of being appliedvia the annulus 38. Otherwise, this configuration of the system 10operates in the same manner as the configuration of FIG. 5.

Referring additionally now to FIGS. 8-10, the well system 10 isrepresentatively illustrated in additional configurations in which theconduit 70 extends to a remote location, as in FIGS. 6 & 7, but thepacker 36 is utilized on the production string 32. Pressure is appliedto operate the valve device 20 via the conduit 70 from the remotelocation, instead of being applied via the annulus 38, but otherwise theconfigurations of FIGS. 8, 9 & 10 operate in the same manner as theconfigurations of respective FIGS. 2, 4 & 5 described above.

It may now be fully appreciated that the above description providesseveral advancements to the art of fluid loss control in wells. Forexample, the system 10 permits the fluid loss control device 20 to beoperated multiple times, and it can be closed after being opened,without intervention into the well. Pressure applied via the annulus 38can be used to close the device 20 after the production string 32 hasbeen installed, for example, prior to retrieving the production stringfrom the well.

The above disclosure provides a method of controlling fluid loss from awellbore 14, with the method including the steps of: installing acompletion string 12 in the wellbore 14, the completion string 12including a well screen 22 and a fluid loss control device 20; theninstalling a production string 32 in the wellbore 14; then engaging theproduction string 32 with the completion string 12; and then operatingthe fluid loss control device 20 by varying pressure in a fluid passage(such as the conduit and/or an annulus 38 formed between the wellbore 14and the production string 32).

The operating step may include increasing pressure in the annulus 38 tothereby close the fluid loss control device 20. The operating step mayinclude closing the fluid loss control device 20 after the fluid losscontrol device is opened.

The production string 32 engaging step may include inserting theproduction string within the completion string 12, thereby placing anactuator 54 of the fluid loss control device 20 in fluid communicationwith the annulus 38 via another annulus 40 formed between the productionstring 32 and the completion string 12.

In the production string 32 engaging step, a packer 16 of the completionstring 12 may be positioned longitudinally between the fluid losscontrol device 20 and the screen 22. The production string 32 mayinclude a packer 36, and the engaging step may further include making ahydraulic wet connect connection between the fluid loss control device20 on one side of the production string packer 36 and the annulus 38 onan opposite side of the production string packer 36.

Also provided by the above disclosure is a well system 10 for use in awellbore 14. The system 10 comprises a completion string 12 including afluid loss control device 20, a packer 16 and a well screen 22, with thepacker 16 being positioned longitudinally between the fluid loss controldevice 20 and the well screen 22. A production string 32 is engaged withthe completion string 12, with the production string including anotherpacker 36. The fluid loss control device 20 is positioned longitudinallybetween the packers 16, 36, and the fluid loss control device 20 isoperable in response to variation of pressure in a fluid passage (suchas the conduit 70 and/or an annulus 38 formed between the wellbore 14and the production string 12).

The wellbore 14 may be gravel packed about the well screen 22.

Pressure may be transmitted between the annulus 38 and the fluid losscontrol device 20 via a hydraulic wet connect 72. The packer 36 may bepositioned longitudinally between the annulus 38 and the hydraulic wetconnect 72.

The system 10 may also include a latching device 66 which releasablysecures the production and completion strings 32, 12, with the latchingdevice 66 being positioned longitudinally between the fluid loss controldevice 20 and the packer 36.

The system 10 may also include a latching device 64 which releasablysecures the production and completion strings 32, 12, with the latchingdevice 64 being positioned longitudinally between the fluid loss controldevice 20 and the packer 16.

The fluid loss control device 20 may be closable in response tovariation of pressure in the annulus 38. The fluid loss control device20 may be openable in response to variation of pressure in an interiorflow passage 50 of the production string 32.

The above disclosure also provides a method of controlling fluid lossfrom a wellbore 14, which method includes the steps of: installing acompletion string 12 in the wellbore 14, the completion string 12including a well screen 22 and a fluid loss control device 20; theninstalling a production string 32 in the wellbore 14; then engaging theproduction string 32 with the completion string 12; then opening thefluid loss control device 20; and then closing the fluid loss controldevice 20 without intervention into the production string 32.

The closing step may include varying pressure in an annulus 38 formedbetween the production string 32 and the wellbore 14. The opening stepmay include varying pressure in an interior flow passage 50 of theproduction string 32.

In the production string engaging step, the fluid loss control device 20may be positioned longitudinally between a packer 16 of the completionstring 12 and a packer 36 of the production string 32.

The fluid loss control device 20 may be positioned between a packer 16of the completion string 12 and a packer 36 of the production string 32in the production string engaging step.

The method may include the step of gravel packing the wellbore 14 aboutthe well screen 22 prior to the production string 32 installing step.

Of course, a person skilled in the art would, upon a carefulconsideration of the above description of representative embodiments,readily appreciate that many modifications, additions, substitutions,deletions, and other changes may be made to these specific embodiments,and such changes are within the scope of the principles of the presentdisclosure. Accordingly, the foregoing detailed description is to beclearly understood as being given by way of illustration and exampleonly, the spirit and scope of the present invention being limited solelyby the appended claims and their equivalents.

1. A method of controlling fluid loss from a wellbore, the methodcomprising the steps of: installing a completion string in the wellbore,the completion string including a well screen and a fluid loss controldevice; then installing a production string in the wellbore; thenengaging the production string with the completion string; and thenoperating the fluid loss control device by varying pressure in a fluidpassage.
 2. The method of claim 1, wherein in the operating step, thefluid passage comprises a first annulus formed between the wellbore andthe production string.
 3. The method of claim 2, wherein the operatingstep further comprises increasing pressure in the first annulus tothereby close the fluid loss control device.
 4. The method of claim 2,wherein the engaging step further comprises inserting the productionstring within the completion string, thereby placing an actuator of thefluid loss control device in fluid communication with the first annulusvia a second annulus formed between the production string and thecompletion string.
 5. The method of claim 2, wherein in the engagingstep, a packer of the completion string is positioned longitudinallybetween the fluid loss control device and the screen.
 6. The method ofclaim 5, wherein the production string includes a packer, and whereinthe engaging step further comprises making a hydraulic wet connectconnection between the fluid loss control device on a first side of theproduction string packer and the first annulus on an opposite secondside of the production string packer.
 7. The method of claim 1, whereinthe operating step further comprises closing the fluid loss controldevice after the fluid loss control device is opened.
 8. The method ofclaim 1, wherein in the operating step, the fluid passage comprises aconduit.
 9. A well system for use in a wellbore, the system comprising:a completion string including a fluid loss control device, a firstpacker and a well screen, the first packer being positionedlongitudinally between the fluid loss control device and the wellscreen; and a production string engaged with the completion string, theproduction string including a second packer, wherein the fluid losscontrol device is positioned longitudinally between the first and secondpackers, and wherein the fluid loss control device is operable inresponse to variation of pressure in a fluid passage.
 10. The system ofclaim 9, wherein the passage comprises a conduit.
 11. The system ofclaim 9, wherein the passage comprises an annulus formed between thewellbore and the production string.
 12. The system of claim 9, whereinthe second packer is positioned longitudinally between the annulus andthe hydraulic wet connect.
 13. The system of claim 9, further comprisinga latching device which releasably secures the production and completionstrings, the latching device being positioned longitudinally between thefluid loss control device and the second packer.
 14. The system of claim9, further comprising a latching device which releasably secures theproduction and completion strings, the latching device being positionedlongitudinally between the fluid loss control device and the firstpacker.
 15. The system of claim 9, wherein the fluid loss control deviceis closable in response to variation of pressure in the passage.
 16. Thesystem of claim 15, wherein the fluid loss control device is openable inresponse to variation of pressure in an interior flow passage of theproduction string.
 17. The system of claim 9, wherein the wellbore isgravel packed about the well screen.
 18. The system of claim 9, whereinpressure is transmitted between the passage and the fluid loss controldevice via a hydraulic wet connect.
 19. A method of controlling fluidloss from a wellbore, the method comprising the steps of: installing acompletion string in the wellbore, the completion string including awell screen and a fluid loss control device; then installing aproduction string in the wellbore; then engaging the production stringwith the completion string; then opening the fluid loss control device;and then closing the fluid loss control device without intervention intothe production string.
 20. The method of claim 19, wherein the closingstep further comprises varying pressure in an annulus formed between theproduction string and the wellbore.
 21. The method of claim 19, whereinthe opening step further comprises varying pressure in an interior flowpassage of the production string.
 22. The method of claim 19, wherein inthe engaging step, the fluid loss control device is positionedlongitudinally between a packer of the completion string and a packer ofthe production string.
 23. The method of claim 19, wherein in theengaging step, the fluid loss control device is positioned between apacker of the completion string and a packer of the production string.24. The method of claim 19, further comprising the step of gravelpacking the wellbore about the well screen prior to the productionstring installing step.